den-ham



(No Model.) 2Sheets-Sheet-1.

A. McG. DENHAM. I

' HEAD REST.

P atentedOot. 19,1897,

INVENTUB WITNESSES NITED 'I Eng,

ALEXANDER MCGOWAN DENHAM, OF SANTIAGO, CHILE, ASSIGNOR TO CLAUDIUS JAMESASH AND WILLIAM HENRY ASH, OF LONDON,

ENGLAND.

' HEAD-REST.

SPECIFICATION forming part of Letters Patent No. 592,002, dated October19, 189'7'. Application filed Julie 5,1897. SerialNo. 639,530. (Nomodel.) Patented in England June 27, 1394,110. 12,477. 1

To all whom it may concern:

Be it known that I, ALEXANDER MGGOWAN DENHAM, a citizen oftheRepublic ofChile, residing at Santiago, in the Republic of Chile, have inventedcertain new and useful Improvements in Head-Rests for Dentists Chairs,(for which I have received Letters Patent of Great Britain, No. 12,477,dated June 27, 18945,) of which the following is a full and completespecification, such as will enable those skilled in the art to which itappertains to make and use the same.

This invention relates to head-rests for dentists chairs, surgeonschairs, and other chairs of this character, and the object thereof is toprovide an improved head-rest which is capaback or rear of my improvedhead-rest; Fig.

2, a top plan view showing one of the 'cush ion-pads, and one of thearms or supports on which the pad is mounted, in horizontal section;Fig. 3, a section on the line 3 3 of-Fig.. 2; and Figs. 4 and 5 aresectional views of de tails of the construction.

In the practice of my invention I employ two arms A, which support thepads H, which are connected by a'broad'elast-ic band B, andthe arms Aare pivotally connected at a) by means of a pivot pin or plug a saidarms being provided with heads through which the pivot pin or plugpasses, and I also provide a disk .or head R, which is mounted on saidpivot pin or plug, and provided withan arm R which is adapted to beconnected in the usual manner, by means of a universal joint J, with theframework of the chair, and the disk or head R is provided onits'opposite sides with segmental recesses R in which are formedratchet-teeth, as shown at B The arms A, which support the pads H, are

carried by a pin or plug a which passes through the center of the heador disk R, and are separately held in position by pawls P, one of whichis shown in 1, said pawls being actuated by springs S.

' The details of the method of connecting the armsA with the ratchethead or disk R are apparent from Figs. 1, 2, and 3. In Fig. 1 each armof the rest is held on the ratchethead by a pawl P, connected therewith,but one of which is shown, said pawl being pressed against the ratchetby the spring S, which is placed in a centralbore or cavity in the endof the arm in which the pawl is also placed. When itis desired to openout either of the arms A, its pawl maybe disengaged from the ratchet bypushing outwardly on the milled collar 0, which is fitted on the end 0fthe .arm containing the pawl and spring,'and operates on the pawl by apin, (shown at D,) which is formed on or secured to a plate (1 providedwith anupwardly-directed projec- "tion 01 and which is connectedwithsaid pawl and passes through a slot formed in the end of the arm A, andthis operation withdraws the end of the pawl P out of engagement withthe ratchet head or disk B.

When .it is desired to elevate the arms, it I is not necessary to movethe milled collar, the upward movement of the arms being free andunimpeded, as will be readily seen from the construction and operationof the ratchet and pawl.

The pads H, carried by the arms A, and connected by an elastic band B,as shown in Figs. 1 and 2, are attached to collars B ,which can beshifted along the arms A, on which they are movably mounted, and towhich they can be secured at any desired point by set-screws, as shownat A in Figs. 1 and 2. The pads H may be of any desired form orconstruction, and may be composed of central plates h, which may beupholstered or covered with any desired material, and the elastic band Bis also preferably covered by the same or any'preferred material.

My improved head-rest is simple in construction and operation, and welladapted to accomplish the result for which it is intended, and it isevident that changes in and modifications of the construction may bemade without departing from the spirit of my invention or sacrificingits advantages.

Having fully described my invention, I claim as new and desire to secureby Letters Patent- 1. The combination with a dentists or other chair, ofa head-rest connected therewith, by means of a universal joint, saidhead-rest comprising a ratchet-head and side arms, pivotally connectedtherewith, said head being also provided with an arm on which is form eda part of said joint, and said side arms being provided withspring-operated pawls or plugs which operate in connection with saidratchethead, and means for operating said pawls or plugs, and to freethem from the ratchet-head, and said side arms being also provided withhead-pads which are connected therewith, substantially as shown anddescribed.

2. The combination with a dentists or other similar chair, of ahead-rest connected therewith, by means of a ball-and-socket joint, saidhead-rest comprising a ratchet-head and side arms pivotally connectedtherewith, said ratchet-head being also provided with an arm 011 whichis formed a part of said joint, and said side arms being provided attheir pivoted ends with central bores, spring-o1' erated pawls or plugsmounted in said central bores, and adapted to operate in connection withsaid ratchet-head,and sliding collars mounted on said side arms andprovided with pins which pass through slots formed in said side arms,said collars and pins being adapted to operate said pawls or plugs, andhead-pads which are connected with said arms, substantially as shown anddescribed.

3. The combination with a dentists or other similar chair, of ahead-rest connected therewith, by means of a ball-and-socket joint, saidhead-rest comprising a ratchet-head and side arms pivotally connectedtherewith, said ratchet-head being also provided with an arm on which isformed a part of said joint, and said side arms being provided at theirpivoted ends with central bores, spring-operated pawls or plugs mountedin said central bores, and adapted to operate in connection with saidratchet-head,and sliding collars mounted 011 said side arms and providedwith pins which pass through slots formed in said side arms, saidcollars and pins being adapted to operate said pawls or plugs, andhead-pads which are connected with said arms,said headpads beinglongitudinally adjustable on said arms, and being also connected by anelastic strip or band, substantially as shown and de scribed.

In testimony that I claim the foregoing as my invention 1 have signed myname, in presence of the subscribing witnesses, this 22d day of March,1897.

ALEXANDER MCGOWAN DENHAM.

\Vitnesses:

M. LAwAsJiBA Wilson, FRANCISCO IINTos.

